Which factor primarily influences the potential erosivity of rainfall?

The potential erosivity of rainfall is primarily influenced by the rainfall amount because it directly affects the magnitude and intensity of runoff, which can lead to erosion. Increased rainfall typically leads to higher volumes of water flowing over the surface, increasing the potential for soil particles to be dislodged and transported. This relationship is especially pronounced during heavy rain events, where the energy of falling raindrops can cause significant soil disaggregation and movement.

In the context of erosion, it's important to note that while other factors like soil moisture levels may influence how readily soil can be eroded, the overall erosive potential of rainfall is fundamentally tied to the quantity of rainfall that occurs. Temperature variations and duration of sunlight have less direct influence on the erosivity of rainfall compared to the amount of rain that falls, as they affect other environmental conditions rather than the rainfall itself.